Would the clearences be any differen't on the shortblock ?

Nope,......

2nd that. Still thermostatically controlled. In theory with raw water cooling or closed your operating temp should likely be somewhere around 160-180 I would guess

T stats for most are 160 or 170 just saying depending on app.

What you do want to pay attention to when looking at a short block you intend to convert to cc is the condition of the water jackets. If they are loaded with rust and flaking you will need to address that or you will clog your heat exchanger.

When i put a boat motor in a car the block got hot and it smoked at wot. Maybe not related but i figured it was because it was " boat clearenced" in the cylinders. My boat cruises at about 130. If the heat exchanger can make the engine run close to the same temps like you guy say . The there is no problem . Thank you!!!